Humoral Immunity Flashcards
Humoral immunity
Mediated by ________, also called _______, produced by _______ cells.
antibodies (Ab)
immunoglobulin (Ig); Plasma
Antibodies generally are found in _____cellular fluids
Eg ____,____,_______
extra
Blood, lymph, mucus
Antibodies are active against agents with an __________ phase, including some viruses, toxins, and bacterial infections
extracellular
Plasma cells are derived from activated ______ that are produced in the _______
B-cells
bone marrow
B cells
B cells display a single homogenous clonal immunoglobulin molecule on their surface.
These immunoglobulins serve as receptors (B-cell receptors [BCRs]) for a specific antigen
Each B cell can respond to only one antigen or a closely related group of antigens.
All immature B cells carry IgM immunoglobulins on their surface
B cells also have surface receptors for the Fc portion of immunoglobulins and for several complement components.
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B cells
B cells display a single homogenous clonal immunoglobulin molecule on their surface.
These immunoglobulins serve as receptors (B-cell receptors [BCRs]) for a specific antigen
Each B cell can respond to only one antigen or a closely related group of antigens.
All immature B cells carry IgM immunoglobulins on their surface
B cells also have surface receptors for the Fc portion of immunoglobulins and for several complement components.
B cells
B cells display a single _____genous clonal immunoglobulin molecule on their surface.
These immunoglobulins serve as receptors (——————-) for a specific antigen
Each B cell can respond to only ______ antigen or a ___________ of antigens.
homo
B-cell receptors [BCRs]
one ; closely related group
All immature B cells carry Ig____ immunoglobulins on their surface
B cells also have surface receptors for the _______ of immunoglobulins and for several complement components.
M
Fc portion
An antigen interacts with the B lymphocyte that shows the best “______” by virtue of its immunoglobulin surface receptor.
The antigen binds to this BCR, and the B cell is stimulated to _________ and_______
The BCR with its bound antigen is _______ by the B cell and the antigen is ______________ that are then ___________________
fit
divide and form a clone (clonal selection).
internalized; degraded to yield peptides
returned to the cell surface bound to MHC class II molecules.
B cell receptor
MHC class ___– peptide complex on B cells is recognized by antigen-specific ________ cells.
CD____ ligand on T cells binds to CD___ on B cells, and the T cell produces cytokines, such as, _____,______,_____ which induce B-cell proliferation.
II; helper (CD4) T
40; 40
IL-4, IL-5, and IL-6,
Bcell receptor
Activated B cells migrate into ______ and proliferate to form __________ that now differentiate into either ________________ cells or ________ cells.
follicles
germinal centers
antibody-producing plasma
Structure of an Antibody Structure of an Antibody
Antibody composed of ______ chains and _______ chains.
These chains bind together to make a ____ shaped molecule
two heavy
two light
Y
The structure of Antibodies may be described by the way they are ___________ by _______.
The stem portion is referred to as the _________
The Y portion with the top third of the stem is referred to as the _____ region.
cut and digested; proteases
Fc region
Fab
Antibodies
The FC region often acts as the _____ for phagocytes during _______ or ______________ cytotoxicity.
The Fab region contains the ————- region
receptor
opsonisation
Antibody dependent cell mediated
antigen binding
The structure of Antibodies
The two sections located at the ends of Y’s arms are called ________ regions.
The variable region is structurally _______ for all ______________________
variable (V)
identical
antibodies synthesized by a particular plasma cell.
The Antibodies from each plasma cell however are different or unique from all other antibodies produced by other plasma cell.
T/F
T
Structure of antibodies
The stem of the antibody molecule as well as the lower portion of the arms called ————— regions.
Most H chains consist of _______ domain (VH) and _________ constant domains (CH).
constant (c)
one variable
three or more
Structure of antibodies
Variable regions are responsible for _____________
constant regions are responsible for the __________ described below:
All plasma cells in the body are _______________
A particular plasma cell may _______________________ producing in order to fight an infection in a different way.
antigen binding
biologic functions
producing one of these classes of antibodies.
switch the particular class of Antibody that it is
Ig___ is the first and main immunoglobulin produced early in the primary immune response.
M
IgM
IgM is present on the surface of virtually _____________ B cells.
It is composed of __________ units (each similar to one Ig____ unit) and ____ molecule of _____ chain
_______mer
____ units held together by _____ bonds
all uncommitted
five H2L2 ; G
one; J (joining)
Penta
5; disulfide
IgM
________ chain functions in the polymerization of monomers
Has _____ anitgen binding sites
J (Joining)
10
Ig______ has the Highest binding capacity and cross linking of all immunoglobulin
M
Ig____ is Most efficient immunoglobulin in agglutination, complement fixation, and other antigen–antibody reactions
M
IgM
IgM does not cross the placenta
T/F
T
IgM
Presence of IgM antibody in the fetus or newborn provides evidence of _______________
immunoglobulins
intrauterine infection.
IgG
Most abundant isotype in serum (____ %)
Predominant antibody in ______ immune responses and constitutes an important defense against ______ and ———.
Cross placenta and play important role in ________
80
secondary
bacteria and viruses
protecting fetus
Ig____ is the Most abundant isotype in serum
G
IgG
— Provides (active or passive?) immunity to unborn fetus.
– Placental cells bind the ______ of IgG and transfer —— across the placental membrane.
Made up of four subclasses (_____,_____,______,_______)
Passive ; Fcportion; Ab
IgG1, IgG2, IgG3, IgG4
IgG
Mediates opsonization of antigen through binding of __________ to _________ on macrophages.
Activate complement system _____-______
antigen-antibody complexes
Fc receptors
Opsonin—phagocytosis
The main immunoglobulin responsible for mucosal immunity
It is found in secretions such as milk, saliva, and tears and in other secretions of the respiratory, intestinal, and genital tracts.
It protects mucous membranes from attack by bacteria and viruses
Plasma cells that release IgA Abs are concentrated along the Mucus Membrane surface.
Provides passive immunity to infants through mothers breast milk
IgA
It is found in secretions such as milk, saliva, and tears and in other secretions of the respiratory, intestinal, and genital tracts.
T/F
T
IgA
It protects ________ from attack by bacteria and viruses
Plasma cells that release IgA Abs are concentrated along the ______________
Provides _____ immunity to infants through mothers breast milk
mucous membranes
Mucus Membrane surface.
passive
IgE
Mediate the immediate ______ reactions (hayfever, asthma, hives, anaphylactic shock)
hypersensitivity
IgE
Mast cells and basophils bind _________ of IgE
_________ of receptor bound IgE molecules by antigen, induces degranulaltion of the Mast and basophil cells
fc portion
Cross-linkage
IgE
Parasitic response
Eosinophils express receptors for IgE
T/F
T
IgD
Found on surface of ______-cells.
Biological function is _______ (thought to function in ____________)
mature B
unknown
activation of B-cells
Protective function of antibodies
Enhanced Phagocytosis
Antibodies produce resistance by ______ organisms, which make them more readily ingested by phagocytes.
opsonizing (coating)
Protective function of antibodies
Virus Neutralization
Antibodies directed against specific viral proteins can bind to the virus and block the ability of the virus particle to attach to its cellular receptor. Since the virus cannot ________, it cannot _______.
invade the cell; replicate
Protective function of antibodies
Neutralization of Toxins—
Antibodies can neutralize toxins of microorganisms (eg, diphtheria,
tetanus, and botulism) and inactivate their harmful effects.
T/F
T
Protective function of antibodies
__________________ Lysis
______________(ADCC)
Enhanced _________
Virus __________
Complement-Mediated
Antibody-Dependent Cell Cytotoxicity
Phagocytosis
Neutralization
Primary immune response
When an individual encounters an antigen for the ____ time, antibody is detectable in the serum within ____________, depending on the _____________ of the antigen and the ____________ (eg, oral, parenteral)
first
days or weeks
nature and dose
route of administration
Primary immune response
The serum antibody concentration continues to rise for _____ and then declines; it may drop to very low levels
The first antibodies formed are ____, followed by _____,______ , or both.
several weeks
IgM
IgG
IgA
Ig___ levels tend to decline sooner than Ig____ levels.
IgM levels tend to decline sooner than IgG levels.
Secondary immune response
In the event of a second encounter with the same antigen (months or years) after the primary response, the antibody response is more ______ and __________________________
This change in response is attributed to the _______ of antigen-sensitive “ _________ ” following the first immune response.
rapid
rises to higher levels than the primary response
persistence; memory cells
Secondary immune response
(More or Less?) IgG is produced, and the level of IgG tends to persist much (shorter or longer?) than in the primary response.
Antibody tends to bind antigen (more or less?) firmly (ie, to have (lower or higher?) affinity) and thus to dissociate (more or less?) easily.
More
Longer
More
Higher
Less
Active immunity
Active immunity is induced after _________________________ (eg, microorganism or their products).
This contact may consist of _______ or _________ infection,
contact with foreign antigens
clinical or subclinical
Active immunity
Can be gotten by Immunization with _____ or ______ infectious agents or their antigens,
________ to microbial products (eg, toxins, toxoids), or ________ of foreign cells.
live or killed
exposure
transplantation
In Active immunity
Host (actively or passively?) produces _________.
Protection is delayed until ___________________
Actively
antibodies
antibody production reaches an effective level.
Passive immunity
Generated by administration of _________
primary advantage is the ___________________
Useful against certain viruses (eg, __________ virus) after a needlestick injury to someone who has not been vaccinated.
preformed antibodies.
prompt availability of large amounts of antibody.
hepatitis B
Passive immunity
__________ reactions can occur if the antibody is from another species.
Hypersensitivity
